Method and apparatus for component control by fuel reformer operating frequency modulation

ABSTRACT

An apparatus comprises a component, a fuel reformer, and a reformer modulator. The fuel reformer is fluidly coupled to the component to supply reformate gas thereto and has a variable operating frequency. The reformer modulator is configured to modulate the operating frequency of the fuel reformer so as to promote maintenance of an operating parameter associated with the component at a predetermined setpoint. An associated method is disclosed.

FIELD OF THE DISCLOSURE

The present disclosure relates to methods and apparatus for operation of a fuel reformer.

BACKGROUND OF THE DISCLOSURE

Fuel reformers are operated to reform fuel into reformate gas (e.g., H₂ and/or CO). Such reformate gas may be supplied to a variety of components to enhance their operation. For example, reformate gas may be supplied to an emission abatement device, an internal combustion engine, or a fuel cell, to name just a few exemplary components.

SUMMARY OF THE DISCLOSURE

According to an aspect of the present disclosure, there is provided an apparatus comprising a component, a fuel reformer, and a reformer modulator. The fuel reformer is fluidly coupled to the component to supply reformate gas thereto and has a variable operating frequency. The reformer modulator is configured to modulate the operating frequency of the fuel reformer so as to promote maintenance of an operating parameter associated with the component at a predetermined setpoint. An associated method is disclosed.

The component may be embodied as an emission abatement device. Exemplarily, the emission abatement device may be a particulate filter (e.g., diesel particulate filter) for removing particulate matter from exhaust gas of an engine or a NOx trap or selective catalytic reduction device for removing nitrogen oxides (NOx) from such exhaust gas.

Illustratively, the reformer modulator comprises a controller electrically coupled to at least one sensor for sensing information related to the operating parameter and electrically coupled to the fuel reformer. The controller comprises (i) a processor, and (ii) a memory device electrically coupled to the processor, the memory device having stored therein a plurality of instructions which, when executed by the processor, cause the processor to operate the fuel reformer, and to modulate the operating frequency of the fuel reformer.

The operating parameter may be, for example, a temperature associated with the component. In the case of an emission abatement device, the temperature may be a temperature associated with the inlet and/or outlet of the emission abatement device. For example, during regeneration of a particulate filter or NOx trap, it may be desirable to maintain the temperature of the inlet at a predetermined temperature setpoint. Excursions beyond the predetermined temperature setpoint could potentially result in thermal damage to the device. Modulation of the operating frequency of the fuel reformer may be used to maintain the temperature at the setpoint to avoid such thermal damage.

The above and other features of the present disclosure will become apparent from the following description and the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified block diagram of an apparatus including a fuel reformer that supplies reformate gas to a component (e.g., engine, fuel cell, emission abatement device) and has a variable operating frequency to be modulated by a reformer modulator to promote maintenance of an operating parameter associated with the component at a predetermined setpoint;

FIG. 2 is an exemplary control routine for use with the apparatus of FIG. 1;

FIG. 3 is a simplified block diagram of an embodiment of the apparatus of FIG. 1; and

FIG. 4 is a simplified block diagram of another embodiment of the apparatus of FIG. 1.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific exemplary embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives following within the spirit and scope of the invention as defined by the appended claims.

Referring to FIG. 1, there is shown an apparatus 10 for controlling operation of a component 12 by use of modulation of an operating frequency of a fuel reformer 14 fluidly coupled to the component 12 to supply reformate gas (e.g., H₂ and/or CO) thereto. The apparatus 10 thus has a reformer modulator 15 configured to modulate the operating frequency of the fuel reformer 14 so as to promote maintenance of an operating parameter associated with the component 12 at a predetermined setpoint to avoid or otherwise reduce excursions of the operating parameter beyond the setpoint, thereby promoting the effectiveness of the component 12.

Illustratively, the reformer modulator 15 comprises a controller 16 and at least one sensor 18. The controller 16 is used to control operation of the fuel reformer 14 in response to input(s) from the at least one sensor 18 which is configured to sense information related to the operating parameter.

The at least one sensor 18 senses information related to the operating parameter and outputs that information on at least one electrical line 24 coupled to the controller 16. The at least one sensor 18 may sense the operating parameter directly or indirectly. In the direct sensing situation, the information related to the operating parameter may simply be the operating parameter itself. Regarding indirect sensing, the at least one sensor 18 may sense one or more other parameters which, taken together, may be indicative of the operating parameter. The information related to the operating parameter may thus be such other parameter(s) indicative of the operating parameter associated with the component 12.

The controller 16 monitors the output of the at least one sensor 18 on the at least one electrical line 24 to receive the information related to the operating parameter. The controller 16 comprises a processor 20 and a memory device 22 electrically coupled to the processor 20. The memory device 22 has stored therein a plurality of instructions which, when executed by the processor 20, cause the processor 20 to perform the functions of the controller 16. Such functions include, but are not limited to, operating the fuel reformer 14 so as to advance reformate gas to the component 12, determining if the operating frequency is to be modulated, and, if so, modulating the operating frequency of the fuel reformer 14 so as to promote maintenance of the operating parameter at the predetermined setpoint.

In determining whether the operating frequency is to be modulated, the controller 16 determines if the operating parameter satisfies predetermined criteria, the predetermined criteria being based on the predetermined setpoint for the operating parameter. If the operating parameter satisfies the predetermined criteria, the operating frequency is modulated.

The predetermined criteria may take a variety of forms. For example, the predetermined criteria may call for frequency modulation if the operating parameter is beyond the setpoint (e.g., outside an acceptable range of temperatures, such as 650° C.+/−20° C., wherein this range is the setpoint) or nearing a boundary of the setpoint (e.g., nearing an upper limit or lower limit of the setpoint). In other examples, there may be a look-up table stored in the controller 16, the look-up table matching possible values of the operating parameter to corresponding operating frequency values. In such a case, the memory device 22 may cause the processor 20 to query the look-up table to determine the operating frequency to be applied to the reformer 14 for a given operating parameter value.

The controller 16 is electrically coupled to the fuel reformer 14 to control operation of the fuel reformer 14. The fuel reformer 14 reforms fuel (e.g., diesel, gasoline) into reformate gas in the form of, for example, H₂ and/or CO. The fuel reformer 14 may be embodied in any of a number of ways. For example, the fuel reformer 14 may be a partial oxidation fuel reformer, a steam reformer, a water-shifting reformer, an autothermal fuel reformer, any combination of such reformers, or the like. Each of these reformers may be embodied as a catalyst having one or more precious metals (e.g., platinum, palladium, rhodium) for catalyzing the respective reaction.

In other examples, the fuel reformer 14 may take the form of a plasma fuel reformer. The plasma fuel reformer may be configured as a type of partial oxidation fuel reformer that receives inputs of fuel, air, and electricity. A fuel valve 26 may be used to control flow of fuel from a fuel source (not shown) to the reformer 14. An air valve 28 may be used to control flow of air from an air source (not shown) to the reformer 14. Electricity received from a power source (not shown) is supplied to a plasma generator 30 which generates a plasma (e.g., an arc) through which the air and fuel are advanced to initiate partial oxidation of the fuel into reformate gas. A catalyst downstream from the plasma generator 26 may be included to increase the yield of reformate gas. Such a catalyst may take the form of any of the aforementioned fuel-reforming catalysts. Exemplary fuel reformers are disclosed in U.S. Pat. Nos. 5,409,784; 5,425,332; 5,437,250; 5,887,554; 6,651,597; 6,702,991; 6,851,398; and 6,903,259, and U.S. Patent Application Publication Nos. 2003/0143442; 2003/0143445; 2003/0140622; 2004/0238349; 2005/0255011; and 2005/0126160, the disclosure of each of which is hereby incorporated by reference herein.

The fuel reformer 14 has a variable operating frequency (e.g., between 40 Hz and about 400 Hz). In particular, each of the fuel valve 26, the air valve 28, and the plasma generator 30 may be under the control of the controller 16 via respective electrical lines 32, 34, 36. As such, the controller 16 may be used to modulate the operating frequency of the fuel valve 26, the air valve 28, and/or the plasma generator 30 to promote maintenance of the operating parameter at the predetermined setpoint. For example, if the operating parameter is a temperature associated with the component 12, the operating frequency of the fuel valve 26 may be increased to lower the temperature or decreased to increase the temperature. On the other hand, the operating frequency of the air valve 28 may be increased to increase the temperature or decreased to decrease the temperature. The operating frequency of the plasma generator 30 may be modulated to adjust the temperature of the reformate gas supplied to the component 12 and thus adjust the temperature of the component 12. As such, the controller 16 may modulate the operating frequency of the reformer 14 so as to promote maintenance of the temperature of the component 12 at a predetermined temperature setpoint if the controller 16 determines that the temperature satisfies the predetermined criteria.

The pulse width of the reformer 14 may also be modulated by the controller 16. In particular, the controller may modulate the pulse width of the fuel valve 26, the air valve 28, and/or the plasma generator 30, thereby further promoting maintenance of the operating parameter at the setpoint.

The component 12 may be embodied in a number of ways. For example, the component 12 may be a component onboard a vehicle. In such a case, the component 12 may be an internal combustion engine, a fuel cell, or an emission abatement device. In particular, the reformer 14 may be used to supply H₂ to the engine for hydrogen-enhanced combustion therein. Reformate gas may be used by the fuel cell in the production of electricity for use onboard the vehicle. The emission abatement device may be embodied as any type of emission abatement device that can use reformate gas in its operation. For example, the reformate gas may be used with a particulate filter to facilitate removal of particulate matter therefrom to regenerate thereof, a NOx trap to remove NOx or SOx (i.e., oxides of sulfur) therefrom to regenerate the NOx trap, or a selective catalytic reduction catalyst to remove NOx from exhaust gas.

Referring to FIG. 2, there is shown a simplified control routine 38 for use with the apparatus 10 or any embodiment thereof (e.g., such as those disclosed in connection with FIGS. 3 and 4). At step 40, the controller 16 operates the fuel reformer 14 to initially establish the operating parameter at the predetermined setpoint. For example, when the operating parameter is a temperature associated with the component 12, the fuel reformer 14 is operated to elevate the temperature to the setpoint (e.g., 650° C.+/−20° C.). At step 42, the controller 16 determines the operating parameter by use of the input(s) from the at least one sensor 18. At the beginning of the process, the controller 16 does this to confirm that the operating parameter is at the setpoint. As the process continues, the controller 16 periodically checks the operating parameter to determine its relationship to the setpoint and, in particular, whether modulation of the reformer 14 is needed. To make this determination, the routine 38 advances to step 44.

At step 44, the controller 16 determines if the operating parameter associated with the component 12 satisfies the predetermined criteria for reformer modulation. If no, the routine 38 goes back to step 42. If yes, the routine 38 advances to step 46 where the controller 16 modulates the operating frequency of the fuel reformer 14 (e.g., the fuel valve 26, the air valve 28, and/or the plasma generator 30) to promote maintenance of the operating parameter at the setpoint. Next, at step 48, the controller 16 determines whether to continue use of the fuel reformer 14. If no, the routine ends. If yes, the routine 38 goes back to step 42. A yes answer may result from, for example, a vehicle shutdown request or, in the case of regeneration of an emission abatement device, may result from controller input(s) indicating that regeneration is complete.

Referring to FIG. 3, there is shown the apparatus 10 in which the component 12 is exemplarily embodied as an emission abatement device that removes emissions present in exhaust gas of an engine 13. In such a case, the operating parameter of interest is a temperature associated with the emission abatement device 12. The temperature may be at the inlet of the device 12, the outlet of the device 12, some combination temperature that is a function of the inlet and outlet temperatures, or other temperature associated with the device 12.

For example, to regenerate a particulate filter, the predetermined temperature setpoint may be a filter inlet temperature of about 650° C.+/−20° C. To promote maintenance of the filter inlet temperature at this setpoint, the controller 16 may modulate the operating frequency of the fuel valve 26, the air valve 28, and/or the plasma generator 30.

In other examples, the emission abatement device 12 may be a NOx trap. Reformate gas may be supplied to the NOx trap to provide a fuel-rich atmosphere about the NOx trap to promote release and reduction of NOx and/or SOx trapped thereby. To promote maintenance of the NOx trap at a predetermined temperature setpoint (the value being dependent on whether NOx or SOx is targeted for release and reduction), the controller 16 may modulate the operating frequency of the fuel valve 26, the air valve 28, and/or the plasma generator 30. Relatively higher temperatures are typically needed for SOx release and reduction. As such, modulation of the operating frequency of the fuel reformer 14 may be particularly useful during SOx release and reduction to avoid or at least reduce the risk of thermal damage that might otherwise occur to the NOx trap as a result of temperature excursions beyond the setpoint. Such thermal management may also be useful with a selective catalytic reduction device or other type of emission abatement device.

The at least one sensor 18 may thus include at least one temperature sensor (e.g., thermocouple). In particular, a temperature sensor may be at the inlet of the device 12 (as suggested in FIG. 3) and/or at the outlet of the device 12. This temperature information may then be provided to the controller 16 via line(s) 24.

In the case where the temperature of the device 12 is to be determined indirectly, other sensor(s) 18 may be used in place of such temperature sensors. For example, the at least one sensor 18 may include, but is not limited to, an oxygen sensor that senses the oxygen concentration in the exhaust gas, a flow rate sensor that senses the flow rate (e.g., mass flow rate) of the exhaust gas, an engine speed sensor that senses the speed of the engine 13, and/or an engine load sensor that senses load on the engine, to name just a few. Such information may be used by the controller 16 to determine the temperature of the device 12 and whether the temperature satisfies the predetermined criteria for modulation and, if so, to modulate the operating frequency of the reformer 14 and possibly the pulse width of the reformer 14 to promote maintenance of the temperature at the setpoint.

The controller 16 and the at least one sensor 18 of the embodiment of FIG. 3 cooperate to provide an example of the reformer modulator 15 of the apparatus 10.

Referring to FIG. 4, there is shown the apparatus 10 in which the component 12 is exemplarily embodied as two emission abatement devices 12 a, 12 b in flow-parallel with one another to remove emissions present in exhaust gas of the engine 13. A valve 50 under the control of the controller 16 via an electrical line 52 controls flow of exhaust gas and reformate gas between the devices 12 a and 12 b. In this way, when the devices 12 a, 12 b are regenerable devices (e.g., particulate filter, NOx trap), the valve 50 controls which of the devices 12 a, 12 b is to be regenerated. Moreover, in addition to being able to modulate the operating frequency of the reformer 14 (e.g., the fuel valve 26, the air valve 28, and/or the plasma generator 30), the controller 16 may also control the position of the valve 50 in a manner that allows adjustment of the amount of reformate gas advanced to the devices 12 a, 12 b and/or adjustment of the amount of oxygen present in exhaust gas advanced to the devices 12 a, 12 b.

The operating parameter may be a temperature of the respective device 12 a, 12 b. As such, there may be at least one temperature sensor (e.g., thermocouple) associated with each device 12 a, 12 b to provide the temperature of each device 12 a, 12 b to the controller 16 for use thereby in determining whether and to what extent to modulate the operating frequency of the reformer 14 and/or adjust the position of the valve 50. In other examples, as discussed above, there may be other sensors that provide information related to the temperatures of the devices 12 a, 12 b to the controller 16 for such purposes.

As such, the temperature or other operating parameter associated with each device 12 a, 12 b may be determined. Further, the controller 16 may be configured to determine if such an operating parameter satisfies the predetermined criteria and, if so, to modulate the operating frequency of the fuel reformer 14, possibly the pulse width of the fuel reformer 14, and also possibly the position of the valve 50 to promote maintenance of the operating parameter at the setpoint for each device 12 a, 12 b.

The controller 16, the at least one sensor 18, and the valve 50 of the embodiment of FIG. 4 cooperate to provide an example of the reformer modulator 15 of the apparatus 10.

While the concepts of the present disclosure have been illustrated and described in detail in the drawings and foregoing description, such illustration and description is to be considered as exemplary and not restrictive in character, it being understood that only illustrative embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected.

There are a plurality of advantages of the concepts of the present disclosure arising from the various features of the systems described herein. It will be noted that alternative embodiments of each of the systems of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of a system that incorporate one or more of the features of the present disclosure and fall within the spirit and scope of the invention as defined by the appended claims. 

1. A method, comprising the steps of: operating a fuel reformer so as to advance reformate gas to a component, and modulating an operating frequency of the fuel reformer so as to promote maintenance of an operating parameter associated with the component at a predetermined setpoint.
 2. The method of claim 1, wherein the modulating step comprises determining if the operating parameter satisfies predetermined criteria that is based on the predetermined setpoint.
 3. The method of claim 2, wherein: the determining step comprises determining if a temperature associated with the component satisfies the predetermined criteria, and the modulating step comprises modulating the operating frequency of the fuel reformer so as to promote maintenance of the temperature at a predetermined temperature setpoint if the temperature satisfies the predetermined criteria.
 4. The method of claim 3, wherein the determining step comprises monitoring output of a temperature sensor associated with the component.
 5. The method of claim 1, wherein: the component comprises an emission abatement device, and the modulating step comprises modulating the operating frequency of the fuel reformer so as to promote maintenance of the operating parameter associated with the emission abatement device at the predetermined setpoint.
 6. The method of claim 1, wherein the modulating step comprises modulating a pulse width of the fuel reformer in conjunction with modulation of the operating frequency of the fuel reformer.
 7. The method of claim 1, wherein: the fuel reformer comprises a fuel valve, and the modulating step comprises modulating an operating frequency of the fuel valve.
 8. The method of claim 1, wherein: the fuel reformer comprises an air valve, and the modulating step comprises modulating an operating frequency of the air valve.
 9. The method of claim 1, wherein: the fuel reformer comprises a plasma generator, and the modulating step comprises modulating an operating frequency of the plasma generator.
 10. An apparatus, comprising: a component, at least one sensor configured to sense information related to an operating parameter associated with the component, a fuel reformer fluidly coupled to the component to supply reformate gas thereto, the fuel reformer having a variable operating frequency, and a controller electrically coupled to the at least one sensor and the fuel reformer, the controller comprising (i) a processor, and (ii) a memory device electrically coupled to the processor, the memory device having stored therein a plurality of instructions which, when executed by the processor, cause the processor to: operate the fuel reformer so as to advance reformats gas to the component, and modulate the operating frequency of the fuel reformer so as to promote maintenance of the operating parameter at a predetermined setpoint.
 11. The apparatus of claim 10, wherein: the at least one sensor comprises a temperature sensor electrically coupled to the controller and positioned to sense a temperature associated with the component, and the plurality of instructions, when executed by the processor, cause the processor to: determine if the temperature satisfies predetermined criteria that is based on a predetermined temperature setpoint for the temperature, and modulate the operating frequency of the fuel reformer so as to promote maintenance of the temperature at the predetermined temperature setpoint if the temperature satisfies the predetermined criteria.
 12. The apparatus of claim 10, wherein: the fuel reformer comprises a fuel valve, and the plurality of instructions, when executed by the processor, cause the processor to modulate an operating frequency of the fuel valve.
 13. The apparatus of claim 10, wherein: the fuel reformer comprises an air valve, and the plurality of instructions, when executed by the processor, cause the processor to module an operating frequency of the air valve.
 14. The apparatus of claim 10, wherein: the fuel reformer comprises a plasma generator, and the plurality of instructions, when executed by the processor, cause the processor to modulate an operating frequency of the plasma generator.
 15. The apparatus of claim 10, wherein the component is an emission abatement device.
 16. The apparatus of claim 10, wherein the component is a particulate filter.
 17. The apparatus of claim 10, wherein the component is a NOx trap.
 18. An apparatus, comprising: a component, a fuel reformer fluidly coupled to the component to supply reformate gas thereto, the fuel reformer having a variable operating frequency, and a reformer modulator configured to modulate the operating frequency of the fuel reformer so as to promote maintenance of an operating parameter associated with the component at a predetermined setpoint.
 19. The apparatus of claim 18, wherein: the component is an emission abatement device, and the operating parameter is a temperature associated with the emission abatement device.
 20. The apparatus of claim 18, wherein the reformer modulator is configured to modulate a pulse width of the fuel reformer in conjunction with modulation of the operating frequency of the fuel reformer so as to promote maintenance of the operating parameter at the predetermined setpoint. 